Vibrating sifting screen



F. PIRLOT VIBRATING SIFTING SCREEN Dec. 20, 1932.

Filed July 26, 1930 J77 vavtn Patented Dec. 20, 1932 UNITED STATES 'FREDERIC PIRLOT, F IXELLES,IILBELGIUM VIBRATIN G SIFTING SCREEN Appllcation fll ed July 26, 1930', Serial No.

In sorting apparatushaving a vibrating sieve in particular, the vibrating sieve may be actuated by a device provided with one or more rotary discs with an unbalanced weight capable of being moved under the action of centrifugal force. Y

In these apparatuses the shafts of the rotary discs are prevented from moving transversely'to the alternating movement to be produced by means of guides against which they bear along a length equal to the amplitude ofthe alternating movement obtained. It thus results that the work of fricion is relatively high. I

For the purpose of reducing this frictional work the invention contemplates supporting the said discs by a pivoted lever. The reduction of the frictional work is the greater the smaller the angular movement of the lever, and consequently the further the pivotal point of the lever is removedfrom the parts supporting the discs.

In apparatus of he known type referred to it is also known to vary the amplitude of the alternating movement byradially moving the unbalanced weight. The devices of this character are generally provided with'two eccentrics located one within the other and of which the angular position may be varied suddenly. It thus'results that the amplitude of the alternating movement varies suddenly in passing from one position to the other of the eccentrics. It is, however, not always possible to obtain the sorting exactly desired. To remedy this inconvenience, the present invention contemplates the possibility of moving the unbalanced weight progressively. This movement may be effected with great facility by traversing a nut secured to the movable weight by a screw threaded rod locked radially, but which can be rotated about itself. The invention also relates to a particular device for actuating the vibrating sieve of a sorting apparatus with a vibrating sieve.

According to the invention this device is. provided with one or more rotary discs with an unbalanced weight capable of being moved under the action of centrifugal force 470,981, and in Be1gium August 3, 1929.

inthe direction of alternating movement to be produced. 'Itis known'to use such devices for actuat ing vibrating frames. In this case, as the whole sieve moves as aunit at the same time asthe frame, a vibration proper of the sieve is not obtained, and this is rapidly obstructed when the meshes are small. It is also known to cause the sieve to vibrate whilst the frame remains stationary. These vibrations are particularly obtained by means of electromagnets which attract the sieve in one direction, then allow itto return to its first position by reason of its tension. In this case, the sieve moves less rapidly than in the case of the vibrating frame. With the actuating device according to the invention the sieve is never obstructed as its vibrationis controlled in a sudden manner in both directions. a b If in a sorting apparatus with a vibrating sieve there are used two superposed sieves it is ,of advantage, in order to obtain good results, that the two sieves make between them a certain angle, generally of some degrees. For the purpose of rendering uniform the manufacture of the frames provided with sieves, the invention contemplates for each frame disposing the sieve in a plane forming with the middle plane of the frame an angle equal to half the said angle. In this manner, for inclining the sieves suitably relatively to one another, it sufiices to place on a definite frame an identical frame which, however, has been turned through 180. about an axis situated in its middle plane and forming with the plane of the sieve an angle equal to half the angle which the sieves should include between them s The invention also includes a device for 0 adjusting the tension of a sieve. It is known to effect this adjustment by moving. the clamps situated along one of the edges disposed transversely to the direction of the tension. These clamps were moved independently of one another in such a manner that it was very difficult to tension the sieve uniformly.

In order to remedy this defect, the invens t'ion contemplates moving simultaneoulsy I through the same amount the said clamps by means of a single mechanism either during operation or whilst stationary.

In order to avoid when modifying the tension of a sieve, that the movement of this produces a certain wedging of the hinges of a rod by which the sieve receives its alternating movementthe invention alsoiprovides that these hinges are such that the rod can pivot freely during the tension of the sieve.

The invention finally-relatesto a' devicefor securing a vibrating sieve for a sorting apparatus.

In such an apparatus there are more finer materials on the portion ofthe sieve'situated underneath thepoint of discharge than on the portion atthe opposite end.

In order to cause this large quantity of fine materials to disappear rapidly the invention contemp'latescausing the said portionloaded witht'heiine materials to be oscillated more energetically than the other portions. For this'purpose, the edge of the sieve along this portion .is secured to the frame by hinges facilitating the vibrations of the sieve.

Other details and features of the invention will appear in the course of the description of the drawing accompanying the present specification and which illustrate in persective,by way of example and not in a limiting sense, a form of construction of the invention.

Figure 1 is a view, ,partly'b-roken away, of a sorting apparatus with vibrating sievesraccordingto'the invention.

Figure 2 is a view'toa larger scale of the device adapted to actuate the sieves.

Figure 3 alsoillustrates to a larger scale means .for actuatingand securing one ofthe clamps serving to hold the sieve,

Figure 1 shows a sortingfapparatus provided with superposed sieves 2 each mounted in a frame 8. These sieves must vibrate by reason of "their connection by means of oscillating rods kto a disc '5zrot'ated, for eX- ample, by a belt 6, the said disc h'avingian unbalanced weight. The action of centrifugal'force on this weight tends to move the disc in the direction which this centrifugal force has at eachinstant.

This movement is .onlyjpermitted in a direction substantially normal to the sieve b mounting the disc .5 ona pivoted lever 7 of whichthe length is relatively large in such a manner that the path described by the centre of the disc 15 may almost be considered as rectilinear and of which the 'midposition is substantiallyparallel to the ,plane of the sieve. 'The "lever 7 is mounted upon the frame 3 bythe pivot 7a. V

In order to vary the amplitudeof the movements of the disc 5 it-i'sparticularly possible to vary the distance between the centre of gravity of the unbalanced wei hted disc from the aris of rotation. This variation of the distance may be effected for example by radially moving a mass 5a carried by the disc 5 (Figure 2).

According to the invention the mass 5a is located in a recess 51) of the disc 5 and serves as a nut for a screw threaded rod 5d prevented from moving radially, but which can be turned about itself. It istlius possible to easily effect a progressive movement of the mass "5a forming the weight of the disc 5.

"When a :sorting apparatus with vibrating sieve is provided, as in the case illustrated in F-igure 1, with a number of superposed sieves it is of advantagefor the sieves to be "arranged relatively toone another at a certain angle,,generally a few degrees.

fIn order to render uniform the manufacture of frames provided with sieves, the inventioncontemplates disposing each sieve 2 in a corresponding frame 3 in such a manner that the middle plane of the sieveis set relatively to the middle plane of the frame at an angle equal "toxha'lf thesaid angle. In this manner a suitableanglebetweenthe two sieves may be obtained'by superposing two identical frames of which one has been turned through "180 relatively to the other about an axis situated in its middle "plane andformin'g with the plane off the sieve an angle equal, to half the angle which the'sieves should have relatively to one another.

For the purpose, of'effectin'g rapidly a uniform adjustment oftheten-sion of all the wires of the sieve, the invention contemplates eflec'ting simultaneously the movement of the cla-m'psby which --th s adjustment is generally effected. For this purpose (Figures 1 and"3-)fthe-fclamps8 which have a screw threaded portion "8a are provid'cd'with a nut "-9 of which 'the periphery 9a is toothed and gearswith a worm 1'0 whichmaybe rotated.for example by operating -a hand wheel 10a. It will be understood that a worm '10 is provided "foreach sieve. These worms pass through suitable bearings mounted on the "frame.

Near one end "of the frame is provided a hopper :11,-by which the materials to be sort ed are discharged on the sieve. In some cases, it may-bedesirable to permit of freedom of movement of the sieve :at this end.

y For this purposeeach rodS passes-through a flange hole in the frame '3 and through -a member 12a having a hole for the passage of-rthe rod -8, this hole being-of the same diameter as the diameter of-this rod. The rod 8 .also passes through a hole in a member 12?), this hole being elongated so1asto-enable the rod .8 to move-11p anddown inwaccordance with the movements of the sieve. In order .to enable the :movement of the rod 8* to take place freely the members 12a and 12b .arewprovided with interengaging correspondingly :shaped spherical surfaces.

:On the end ofthe sieve opposite to that .I-lO

upon which the hopper 11 is situated, the sieve is clamped by ordinary fixed clamps not shown.

Finally the invention also contemplates that the rods 4 connecting the sieves together as also the upper sieve to the mechanism imparting the alternating movement thereto are formed in such a manner that the adjustment of the tension of the sieve does not produce a wedging of the hinges. In Fig. 2 there is shown in detail the rod 4 which connects the upper sieve 2 to the lever 7. Tension is effected by moving the clamps 8 of Fig. 1 in the direction of the arrow X so as to stretch the sieve. I

The pivot 4a which connects the rod 4 to the lever 7 is positioned perpendicularly to the direction X in which direction tension takes place. A bar such as 13 distributes throughout the length of the sieve the action transmitted by the rod 4:.

It will be understood that the invention is not solely limited to the form of construction illustrated and that modifications may be made in the shape, the arrangement and constitution of the elements partaking in its construction without departing from the scope of the present invention.

What I claim is:

1. A sifting apparatus comprising a fixed frame, sieves therein, a rotatable unbalanced weight, a pivoted lever for supporting'the axis of said rotatable unbalanced weight, means for rotating the latter and rods between the pivoted lever and the sieves disposed substantially perpendicular to the latter for transmitting directly to the latter the vibration of the pivoted lever in a direction perpendicular to the plane of these sieves.

2. A sifting apparatus comprising a fixed frame, a sieve therein, a rotatable unbalanced Weight, a pivoted lever for supporting the axis of rotation of said rotatable unbalanced weight, means for rotating the latter, a rod between the pivoted lever and the sieve disposed substantially perpendicular to the latter for transmitting directly to the latter the vibrations of the pivoted lever in a direction perpendicular to the plane of this sieve, means for varying the tension of the sieve and pivots for connecting the said rod to the pivoted lever and to the sieve, the axes of said pivots being directed transversely to the direction of tension of the sieves.

3. A sifting apparatus comprising a fixed frame, sieves therein, a rotatable unbalanced weight, a pivoted lever for supporting the axis of rotation of said rotatable unbalanced weight, means for rotating the latter, a rod between the pivoted lever and the adjacent sieve disposed substantially perpendicular to this sieve for transmitting directly to the latter the vibrations of the pivoted lever in a direction perpendicular to the plane of this sieve, rods between the successive sieves,

transverselyto the direction of tension of the sieves. I

In testimony whereof I affix my signature.

FREDERIG PIRLOT. 

